./. ; /. IJurnc11: "Middle" Cr~taceous morphological divcrs ny ...... p. 57 - 65 .

Journal of Nan noplankton Research_ 19. I_ 1997 .

'MIDDLE' CRETACEOUSMORPHOLOGICAL DIVERSITY WITHINTHE GENUS CERATOLITHINA MARTINI, 1967
.Jackie A. Bl!rnell. Department olGeologica/ Sciences. Un iversity College London, Cower Street,
London, WC/ E 6BT. UK

Abstract: During the course or a study or the ·M iddle - and ·Upper Creta ceous or the Indian Ocean, a wide
variety or Cera folithina Martini _ 1967 morphologies and size- ranges was observed with the li ght-mi crosw pe in :111 apparently expanded l Jp1kr i\lbian to Upper Cc nomanian seq uence from Deep Sea Drilling
Prnj~ct (DSDP) Site 25X . Site 25S is prese ntly situated at 33 °47 .69 -S_ II2 °2S .42"E on the northernllank or the Na turali stc Plateau . niT SW Australia . Such variety and relativel y frequent abu nd anc~ or(era/0/itlnna seems not to have been reconkd elsewhcr~ . Three new s p~~ie s_ Ccra toti thina copis.
( 'emtolithina duplex and Cemwlitlnna natura!islepl(l(eaucnsis. and tlncc new subspec ies. Caatolithina
cmxii subsp . capllmlea_ ( 'eratolifluna duplex suhsp . ge111ina and ( 'cmfolithina lwmafa subsp . .fct!cata an:
de sc ribed . Prcscrvational implications arc discussed _ i\ lineage is conjectured .

nus fl·om clay lithologies_ and other reports (op cif. ) arealso mainly from this lithology. This may constitute evi dence to suggest that Ceratolilhina: (i) is more resistant
to corrosion than other nannofossils, thus allowing it tobecome apparent ly relatively abundant, or more easily
observed, in poorly-preserved material (a lthough the Gaultformation, from which Perch-Nielsen ( 1988) described C
comula and C. cru:rii, contains rather well-preserved
nannolloras): and/or (ii) may have preferred to inhabit
deeper-water and/or restricted-circulation environments .

ProvenanceMartini ( 196 7) originally reported Ceratolithina hamata
fi·om the Albian of NW Germany. Perch-Nielsen ( 1988) described Cerato/ithina hicornuta and Cerato/ithina cruxii
from the Albian of SE England. Both these localities li e
withi n the boreal palaeobiogeographical region. Although
few in number, other reports of Cerato/ithina also appear
to be restricted to relatively high northern palaeolatitudes(e.g the North Sea and UK area: Crux, 1991: Varol & Girgis,
1994: Jeremiah. 1996). Burnett (in Gale et al., 1996) also
recorded Ceratolithina at particular horizons inmarls fl·om
the Mont Risou section of the Hautes-Alpes (SE France).
This latter location contains palaeobiogeographically mixed
nannotloras (e.g the eo-occurrence in the section of
Nannoconus spp. with Repagulum parvidentaftztm.
Serihiscutum primilivum and Calculiles anji·ac/us) andis believed by Burnett (up. cif.) to have occupied a position close to the edge of the boreal region during the Albian
to Cenomanian which experienced alternating boreal andtethyan influences. DSDP Site 258 was located at 57.4°S in
the Albian-Cenomanian (according to an ATLAS™
palaeogeographical projection for this interval), and contains nannofloras characteristic of the austral
palaeobiogeographical realm , i.e. it is a high southernpalaeolatitude site. The author is unaware of any reportsof this genus from low-latitude sequences. It seems likely,
therefore_ that Ceratolithina was a predominantly highlatitude, bipolar genus, which may indicate that it thrived
in relatively cool oceanic conditions (although the global
temperature gradient during the Albian-Cenomanian isbelieved to have been much lower than it is now. the poles
being ice-ti·ee).
Thierstein ( 1974) logged the nannofossils for Leg· 26 of the DSDP but made no mention of Ceralolilhina at
any of the sites. Bown (pers. comm .. 1996) found C
hic01·mtla in Albian sediments at Sites 257 and 259, andC. hicornuta and C. hamata in the Albian of Site 258. This
study has shown that at DSDP Site 258, Ceratolithina
was unusually frequent in soft, laminated clays and sha lesin which the attendant nannofloras were mainly poorlypreserved and of low abundance. Both Martini ( 196 7) andPerch-N ielsen ( 1988) first identified the spec ies of this ge-

Cerato/ithiua morphology
Ceralolithina possesses only a few morphological components (Figure I). A rod is common to all species, andthis tends to be rounded at the ends. The rod supports
horns (scythe-like), rectangular blade-like structures, andtriangular to concave-triangular sai l-shaped structures.
Where a spec ies possesses more than one of these features, they may or may not lie in the same plane. Herein,
the anterior end is designated as the end of the centra l rod
which bears the bulk of the largest feature(s), whi lst theposterior end of the rod may bear smaller horns or blades,or may not bear any feature. In the Iight-microscope, members of the genus appear to act as a single crystaL It has
low birefringence for such a relatively thick form, suggesting that the c-axis is not in the plane of the nannolith.
Light-microscope observations have shown that the caxis lies at 45 ° to the rod. This crystallographic structure issignificantly different to the Tertiary genera Amauro/ithus
and Cerawlithus, in which the c-axis is perpendicular tothe plane oft he nannol ith in the former, and in the plane of
the nannolith but perpendicular to the arms in the latter (J.
Young and P. Bown, pers. comms, 1997).
'
The genus has been described as being morphologicall y si milar to the genera llmauro/ithus andCeratolithus (e.g. Martini, 1967; Crux & Lord, 1982). bothof which first appeared in the Neogene. However, it is unlikely that Ceratolithina is related to either of these taxa
because (i) Cerato/ithina has not been observed in the
Cretaceous stratigraphically higher than the Cenom '!nian/'
Turonian boundary interval (herein and pers. obs.), so that
there is no direct evidence fo r descendancy , (ii)57

Journal of Nannoplankton Research , 19. I, 1997.

anterior

J ,J. Burne/1. "Middle" Cretaceous morphological diversity ...... p. ~7 • 65.

Family: lucertae sedis
Genus: Ceratolithiua Martini, 1967
Type Species: Cerato/ithiualwmata Martini, 1967

c-axisorientation''

Ceratolitlliua copis .\p. mm
Figure 2e; Plate I, Figures 24-26,29-31

rectangular
blade

Holotype: Plate I, Figure 26.
Stratigraphical horizon: 258-15-6. 95-96cm, CC9c, Lower
Cenomanian.
Type locality: DSDP Site 258, Naturaliste Plateau, SE Indian Ocean.
Derivation of name: Latin cop is = cleaver, referring to theappearance of its blade.
Diagnosis: A rod bearing a relatively large, rectangular to
subtrapezoid b.lade, with or without a second, smaller blade.
Description: A number of different morphologies are attributed to this new species (see Figure 2e). In type A, therectangular blade is positioned at the anterior end of therod and extends down to aropnd three-quarters of thelength of the rod . Another, much narrower blade Iies on
the opposite side to the first, apparently in the same plane,and extends down almost the entire length of the rod . A
third, very narrow blade lies apparently perpendicularly tothe second blade. Type B has a rectangular blade which is
attached to the middle portion of the rod, with a single,
much narrower but longer blade lying on the opposite side,
and also attached to the middle portion of the rod. Type C
has a rod with a trapezoid to subtrapezoid blade on one
side, with or without a second, narrower blade on the opposite side. It is possible that etching along the margins of
the trapezoid blade caused the curved outline illustrated
in Figure 2e. ?C. copis may have been modified by etchingof the blades.

rod~posterior
Figure 1: Ceratolithina morphologicalterminology. Stippling implies different
plane
Ceratolithina has a much less complex morphology than
the younger genera (compare Figure I herein to PerchNielsen, 1985a, p.454, fig.l5), and (iii) the two younger genera are low-latitude, open-ocean taxa (Perch-Nielsen, 1985a,
p.457). This is in agreement with Perch-Nielsen ' s ( 1979,
1985a) view. She suggested that the Neogene forms
evolved fi-om the Miocene genus Triquetrorhahdu/us (thiswas prior to her description ( 1988) of Triquetrorhabdulus?
shet/andensis from the Valanginian of the northern North
Sea but which she believes is nvt related to the Miocene
forms either). Indeed, Raffi & Flores ( 1995) have observed
forms intermediate between Triquetrorhabdulus andAmaurolithus.
It has also been speculated that Cerato/ithina isrelated to the Campanian-Maastrichtian genus
Ceratolithoides Bramlette & Martini, 1964 (e.g. Martini,
1967; Crux & Lord, 1982). This relationship also seems
unlikely, since (i) Ceratolithoides morphology is substantially different, early forms of Cerato/ithoides having a
conical morphology which evolves into a flattened arrowhead-shape with bilateral symmetry, (ii) Ceraw/ithoides isa well-documented low-latitude taxon, and, again, (iii) there
is no evidence that Ceratolithina lived beyond the
Cenomanian, or that Ceratolithoides first occurred below
the Campanian. Again, this is in agreemetit with PerchNielsen's ( 1979, 1985a, b) view.

Ceratolithimt cruxii Perch-Nielsen, 1988 subsp.
cruxiiFigure2c; Plate I, Figures8-ll, 15-18
1988

Ceratolithina cruxii Pcrch-Niclscn: pJO. pi. I. li gs 5-7 .

Holotype: Perch-Nielsen, 1988, pi. I, fig.5.
Stratigraphical horizon: Bed VII, CC8b. niobe Ammonite
Zone. Middle Albian.
Type locality: Copt Point, Folkestone, Kent, SE England.
Definition : Nannofossil with a straight to very slightly
curved horn and one or more lateral blade(s).
Remarl<s: Two types were distinguished in this study.
Type A has a sail-shaped blade attached to almost theentire length of the rod, with a second, narrow. rectangularblade attached to almost the entire length, but on the opposite side of the rod. Type B has a narrow, triangularblade attached to almost the entire ro~-length, and may or
may not possess a second, rectangular blade. Variants ofboth types also occur with a much elongated rod, the triangular blade being attached to only the anterior portion·
ofthis.

Cerato/ithiua diversity and taxonomy
Only three species have previously been assigned to
Ceratolithina. The diversity identified in this study centred around the shape, size, number and orientation of
blades attached to the central rod (Figure 2), and the factthat distinct biostratigraphical distributions could be d ~t­
fined (Figure 3) using these morphological features. 'Twinning' was also encountered.

58

J. A. Burne/1: "Middle" Cretaceous morphological diversity ..... , p. 57 - 65 .

Journal ol' Nannoplankton Research , 19. I . 1997 .

.
a

~

b

c

1 4 Ll 1
c4
m
qCl
~n
~ 2l lq~'~~L

C. hamatasubsp. hamata

C. bicornuta

drawn from
Perch-Nielsen(1988, 1'1. 1, figs I ,2)drawn from Perch-Nielsen(1988, 1'1.1, figs 3, 4)

C. hamatasubsp.
falcata

type B

type AC. cruxii subsp. cruxii
drawn from Perch-Nielsen(1988, PI . I, figs 5, 7)

d

/

~

C. cruxii subsp.

capitanea~

C. duplex
subsp. gemina

/

e

~·

'

'

type A

type B

C. duplex subsp. duplex

type A

type Brtype C

type C'

type A

type B

C. copi•

type C

C. naturali•leplateauemi•

Figure 2: Ceratolithina morphological diversity.
Stippling implies different plane

typeC?C. copi•

Ty pe loca lity: DSDP Site 258,
Naturaliste Plateau, SE Indian Ocean .
Derivation of na me: Latin duplex =double, referring to the characteristic 'stacked twinning' observed in
the taxon .
Dia gnos is: Each individual comprises a rod bearing a rectangularblade which extends down the entire length of the rod. In a similar orientation but in a different plane, therod bears a sail-shaped to bluntended sail-shaped blade, which is
attached to approximately half of thelength of the rod. These individuals
are 'twinned' in such a way that one
individual is sutured to its neighbour
along the anterior/posterior ends
(see Figure 2d). The sutures between
the individuals may not be obvious
in specimens which are poorly-preserved, wherein the form appears tohave a single rectangular blade anda complex double-sai l-shaped blade.
Desc ription: Two types were distinguished within the concept of thissubspecies (see Figure 2d). Type A
individuals have a sail-shaped blade
attached from the anterior end of therod to half-way down the rod, and asecond, much narrower rectangularblade in an opposite orientation to
the first two, and extending down theentire length of the rod . Type B individuals possess a blunted sailshaped blade attached to the anterior end of the rod, and apparently
lack a third blade.

Cerato/itltina crux ii Perch-N ielse n, 1988 subsp.
capitanea subsp. nov.
Figure 2c; Plate I, Figure 4

Ceratolitltin a duplex .\p. n ov. subs p. gemina sub.\]J.

Ho lotype: Plate I, Figure 4.
St ratig ra phica l horizon: 258-16-1 , 144cm, CC9b, Upper
Albian-Lower Cenomanian.
Type loca lity: DSDP Site 258, Naturaliste Plateau, SE Indian Ocean.
Derivation of na me: Latin capitaneus = chief in size, large,
referring to the size of the taxon .
Diagnosis: A large form (see plate) composed of a rod
bearing a single, lateral blunt-sail-shaped blade attached
down the entire length of the rod.

Holotype: Plate I, Figure 28.
St rat igrap hica l horizon: 258-15-1 , 141-142cm. CC I Oa,
Lower-Upper Cenomanian.
Type loca lity: DSDP Site 258, Naturaliste Plateau, SE Indian Ocean.
Derivation of name: Latin geminus = twin, referring to thehabit of 'mirror-image twinning' observed li>etween individuals.
Diagnosis: Individuals are composed of a rod bearing a
relatively large, rectangular blade which extends down theentire length of the rod. In a similar orientation but in adifferent plane, a sail-shaped blade is attached to the rod
for almost the entire length of the rod. 'Twinning' in thissubspecies differs from that observed in Ceratolithina
duplex sp. nov. subsp. duplex subsp. nov. in that indi_viduals are sutured along the lateral axis opposite to the rod,forming a mirror image of one another (see Figure 2d).

II OV.

Figure 2d; Plate I, Figure 28

Ceratolitltina duplex !~>p. nov. subsp. duplex subsp. 11ov.
Figure2d; Plate I, Figure27

Holotype: Plate I, Figure 27.
Stratigraph ica l horizon: 258-16-5, 36-37cm, CC9b, Upper
Albian-Lower Cenomanian.

59

Journal o f Nannoplankton Research. 19. I. 1997

J A. Burnell : "M iddle" Cretaceous morphological diversity ...... J1 . )7 - 6) .

Figure 3: Ceratolithina distribution, Indian Ocean DSDP Site 258*data from Bown (pers. comm., 1996)
<(
Q)

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C'·

barren & no Ceratolithina above this level~~:::.s;:a>W [D~(!) :;,~
<

(/)~

U)

lll1iit- C:Ql

CC10B

R F R R R
F
F c
R
R
R
R R R R F F R
c F F c CC10A
R
R
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R F R R F
R F
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F
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R
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9A
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no Ceratolithina recorded
R
F
R
F
F
R
R

cess

R
R

ea

::;c ·-E

z

F
F

<
z
<
:::2:
0

z
w

()

z

<
z
<>:::2:0:
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zo
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()::J

--o
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<
il5

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<

z

<

il5

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0

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R

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:::2:

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no Ceratolithina below this level

Ceratolitftimtfuttttata Martini, 1967 subsp.lumwtit

CC8A

LA. ALB.

of different size and curvature extend laterally and in thesame orientation from a rod. The rod extends beyond theanteriorally-positioned horn , forming ai1 apical spur.

Figure 2b; Plate I, Figures 5, 6
1967
198'8

o6

W O)

:~

<J

14-1, 40-41cm
14-1 , 141-142cm
15-1 , 141-142cm
15-2, 33·35cm
15-3, 35-36cm
15-4,102-103cm
15-5, 43-44cm
15-6, 95-96cm
16-1 , 144cm
16-2, 114-115cm
16-3, 31-32cm
16-4, 45-46cm
16-5, 36-37cm
16-6, 15-16cm
17-1, 27-28cm
17-2, 38-39cm
17-3, 63-64cm
17-4, 45-46cm
17-5, 110-1 11cm
18-1, 66-67cm
18-2, 104-1 05cm
18-3, 116-117cm
18-4, 124-125cm*18-4, 143cm*19-CC*20-1, 87cm
*20-1 , 128cm*21-1, 97cm
*2 1-1 , 138cm*21-2, 61cm
*21-2, 124cm*21-3, 5cm*21-3, 140cm*22-1, 86cm
*22-1 , 130cm*22-3, 28cm
*22-3, 92cm
*22-5, 48cm
*22-5, 81cm
*22-5, 112cm*23-1,147cm.!!?

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..J
f:::co<-c:"""'g. 2 2 1:l 1:l ill,O>Ol:.s
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t
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8 g. 01:l 1:l ~ -c:"' -c:"' ~ "'c: "'c: ~c: ·E "' -5 .g LL.
C.£2·u; .~"' .s"' .s"' .s"' .s-s"' .s"' .s"' .s"' .s"' .s"' .s"' .s"' .s"' .s-c:"' .s"' .s"' .Qc: <! ""' 2 !!l0 zo .!:!?z.s-s -s -s ~ 2 ~ ~ ~ -s ~ ~ -s -s~ ~ -s -s!!l ~Q. l!!
"z cn..c2 2 2 2 e 2 2 2 2 2 2 2 2 ~ 2 2 ~ :=::::
e<I> e<I> e<I> e<I> (3 e e<I> e<I> e e<I> e<I> e<I> e e<I> !!! e e & :§e "' ~c: c( CD~
I.)
I.) I.) I.)I.)" I.) I.) I.)" I.) I.) I.) I.)"' I.) I.)"' I.) 8 ijj -J ~ ~ z 1ii~
Q)

SAMPLEa.

MARKER
SPECIESz- z- z-a.
<(a.

Ceratolithina hamata Martini : p.295-21.J6. pl.30. figs 1-3.
Cera tolithina hamata Mitrttnt : Pcrch-Niclscn . pi. I. fig . I.
0 non pl.l , fi g.2.

Ceratolithillalumwta Martini, 1967 subsp.falcata.m b.\jJ. IIOV.
Figure 2b; Plate I, Figu re 7

Holotype: Martini, 1967, pl.30, figs I, 2.
Stratigrap h ica l horizon: At 346m in the Konrad 2
Borehole, minimus Clay, Middle Albian.
Type loca lity: Salzgitter-Watenstedt, NW Germany.
Derivation of name: Latin hamatus = hooked .
·Description: Fish-hook-shaped form in which two horns'> 1988

Ceratolithina hamata Martini . 1967 : l'erch-Niel se n. pi. I,''fig.2, 11011 pi. I , Jig. I .

Holotype: Plate I, Figure 7.
Stratigrap h ical horizo n : 258-14-1, 141-142cm , CC lOa,
Lower-Upper Cenomanian .

60

Journal of Nannoplankton Research. 19. I, 1997 .

.J. ; I. /Jurne/1: "Midd le" Cretaceous morphological diversity ..... , p. 57 - 65 .

c

UPPER ALBIAN

MIDDLE ALBIAN]"

inllatumlautusloricatus

0

:;;:

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:0
)>

r

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ii:

....~ 3~ .g· §~ [~! ~ (SUB)STAGE. ~AMMONITE ZONE
after Rawson et al. (1978)

~

.

£

~

..~ t

AMMONITE SUBZONEi

APPROXIMATE CORRELATION OF
COPT POINT BED Is WITHAMMONITE SUBZONES
after Jeremiah {1996)

roO

,

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ii
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after Sissingh (1977) &Perch-Nielsen (1985);
correlation wilh ammonite subzones alter Galeeta/. (1996)&
interpretation after Jeremiah (1996)

I

I

I

Martini (1967)
Salzgitter Watenstedt, N Germany
Perch-Nielsen (1988)
Cop! Point, Folkestone, SE England

Jeremiah (1996)

A Arlesey
8 Burwell
CB Chamberlain's Barn
CGCowGap

GP Cop! Point
D" EC English Channel BH

n· FW Folkestone Warren BH~ NAP Nine Acres Pit

E SF South Ferriby

S' SH BGS Soham BH,.,W-l-.WW...J..'-,.J-J-W.,;..J....,..J..J..U..J,..,J.....hi-.J..W.....!.+--4++-+-f-+++-J--I-+!--t+-1-111 •t baseof section
top of section~mm~TinTIWTITITirr~~~TIT~m
11~;~
'I

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.,

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1

H++-f-+++-l-++H++-H++--i-++H++-f-+++-I-++H++-11-++H+--I-+L:..L-'-,f-++hli++-lf~~~~~~:u.~~·F~~~~ <1996lli
Burnett (herein) &Bown (pars. comm., 1996)

DSDP Sites 257, 258 & 259, SE Indian
Ocean

~

g>l

9a-b

8b

r ~T ;,rlIil < 1!
1

1

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Diagnosis: A rod bearing a single, moderately-sized horn,
situated at the anterior end of the rod.
Remarks : Since this form shows no evidence of having
possessed two horns, it is considered to b~ suffic iently

Type locality: DSDP Site 258, Naturaliste Plateau, SE Indian Ocean.
Derivation of name: Latinfalcatus = sickle-shaped, referring to the appearance of the single horn.

61

Journal of Nannop lankt on Resea rch . 19, I. 1997 .

m..
··1~ __ Tt-::::1

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-

Figure 5: Tentative Ceratolithina lineage, based on published data

differentiated from C. hamata subsp. hamata to warrant
subspecies status. The form illustrated by Perch-Nielsen( 1988, pi. I, fig.2) may be a broken C. hamata subsp.
hamata. and is thus not designated as the holotype . This
subspecies may possess an elongated rod .

Ceratolitlliua lutfuralisteplateauensis sp. nov.
Figure2f; Plate I, Figures 12-14,19-23
Holotype: Plate I, Figpre 13 .
Para types : Plate I, Figures 14, 19, 20, 21.
Stratigraphical horizon : 258-15-3, 35-36cm, CC9c, Lower
Cenomanian.
Type locality: DSDP Site 258, Naturaliste Plateau, SE Indian Ocean .
Derivation of name : After the Naturaliste Plateau uponwhich Site 258 was drilled.
Diagnosis : A rod bears two horns positioned at the anterior and posterior ends of the rod but apparently joined(see Figure 2t). The larger ai)terior horn (or possibly a
blade) is triangular in outline, joined to the rod below theend of the rod thus forming a small, apical spur. The smaller
posterior horn is attached to the opposite end of the rod .
A second small, posterior horn lies·in an opposite orientation to the first posterior horn but in a different plane, suchthat it is often hidden from view in the light-microscope.
Description : Three types were distinguished which may
may not reflect preservational effects (see Figure 2t).

or

62Type A is used to define the taxon(see diagnosis) . Type B has a morepronounced join between the similarly-oriented horns, which are alsoof similar size. At the anterior end of
the form, a small, rectangular blade
Iies in the same orientation but in adifferent plane to the anterior horn .
In type C, only the two, small, ?posterior horns are present.

§-

e

.C)

§-

q

----

~

..:::

4 ~ 1~
1H-::::1

---

s

E

~

~

s

-

z
-<

;

~

.

::

~

..::

s

~>
----C~:..l

Cl:~
r.J_
Q.=:l

~

:::"''ll0.1. A. Bumett: "Middle" Cretaceous morphological divers ity .... , p. 57 - 65 .

Biostratigraphy and lineage
speculations
Figure 3 shows the biostratigraphicaldistribution s of Ceratolithina andthe marker-taxa in Site 258,
Naturaliste Plateau, SE Indian Ocean.
Ceratolithina was identified between samples 17-5, 110-111 cm and14-1, 141-142cm, an interval interpreted as lying within NF Subzones
CC9a-b to CC 1Oa and therefore
equivalent to the Albian/Cenomanianboundary interval to the Upper
Cenomanian, according to Burnett( 1996). The addition of data fromsamples stratigraphically below thisinterva1(18-4, 143cmto23-l, 147cm,
CC8b-9a: Bown, pers. comm. , 1996)
provides a complete view of this genus at this site. Ceratolithina has
also been recorded at Sites 24 7 and249 in the SE Indian Ocean (Bown,

pers . comm. , 1996). An interesting phenomenon is the absence of Ceratolithina between cores 2 1-3 and 18-1. If
this taxon is a cooler-water form , then it is possible that
this absence is due to a warming episode at 57.4°S during
the Middle Albian-Early Cenomanian. Burnett et al. (inpress) show some evidence to support this. They describe
poleward excursions of coccolith taxa, defined as intermediate-latitude-preferring, at high southern latitudes for thisinterval in the Indian Ocean. There is no evidence at present
to support warming as a cause for the absence ofCeratolithina from the Cenomanian of the North Sea.
In order to surmise a lineage for Ceratolithina, it
was first necessary to determine the reported first and last
occurrences (FOs/LOs) of each taxon. Figure 4 sets theseout. Martini ( 1967) described hamata (subsp. hamata) fromthe 'minimus Mm·ls' which are of Middle Albian age. PerchNielsen ( 1988) reported cruxii (subsp. cruxii) andbicornuta from the Gault Clay Formatioll, with the FO of
cruxii (subsp. cruxii) at the base of the Middle Albian,and the range of bicornllla spanning the Middle-Upper
Albian boundary. Crux ( 1991 , p.2 14) lumped hamata andcruxii together in his range-chart, so his data is omitted
from Figure 4. Jeremiah ( 1996) examined numerous sections, and Figure 4 shows the FOs and LOs of the species
in each section, such that composite ranges can be worked
out from his data. Thus, he is in agreement with PerchNielsen on the FO of cruxii (subsp. cruxii) at the base of
the Middle Albian and also the base of CC8b (FO of

J A. Burnefl .· "Middle" Cre taceo us morpho log ica l divers ity ...... p. 57 - 65 .

Tranolithus oriunatus); he found the FO of bicornuta
sl ightly stratigraphically lower than Perch-Ni elsen did, if it
is true· that his record of this taxon in the BGS Soham
13orehole is from a displaced sample (Jeremiah, 1996, fi g.7note), but he also found its LO to be lower, pl acing it at the
top of the Middle Albian rather than the base of the Upper
Albian. He placed the FO of hamata (subsp. hamata) justabove his FO of bicornuta at Copt Point (again, if theSoham Borehole sample is di splaced), in the Middle Albian.
Sown (pers. comm., 1996), however, found bicornuta to
first occur wi h Axopodorhabdus· albianus in Sites 257
and 259, which places its FO lower in th e Middle Albian
than either Perch-Nielsen or Jeremiah beli eved. He also
found that the LO of bicornuta in the SE Indi an Ocean
heralded the period of Ceratolithina-free sed imentation
postulated above as being a warming episode. Burnett (inGa le et al., 1996) recorded cruxii subsp. cruxii and hamata
subsp. hamata around the Albian/Cenomanian boundary,whilst the data presented herein provides LOs for the taxa.
The stratigraphical positioning, and the abrupt nature, of
these LOs appears to indicate a link between the extinction of the genus and the Cenomanian-Turonian Oceanic
Anoxic Event.
Based on these ranges, and on gross morphological characteristics of the speci es and subspec ies, a putative lineage has been drawn (Figure 5). Perch-Nielsen ( 1988)
specul ated that C. cruxii might have been the ancestor to
C. hamata and this appears to be th e case, poss ibly via C.
bicornuta. C. hamata gave ri se to C. ham ata subsp.
falcata, and probably also to C. naturalisteplateauensis,
altho ugh this latter form mi ght just as easily have comefrom C. cruxii. C. cruxii is believed to have given ri se to C.
copis, C. duplex and C. cruxii subsp. capitanea.

Journal of Nann o plankton Research . 19. I. I 997 .

C rux ..I. A. 199 1. Albian ca lca reou s nannoro ss il s rrom ,theGau lt C lay or Munday ' s Hill ( Bedford s hire, Eng land).
Journal ojMicropalaeontology. 10(2): 203-221 .
Crux ..I. A. & Lord. A. R. 1982 . Di sc uss ion. In: A. R. Lo rd(Ed.). A Stratigraphical lndex of Calcareous Nannofossils:
168-1 73. British Micropalaeontolog ical Society Series.
Ell is Horwood Limited, Chichester.
Ga le, A.S, Kennedy, W ..l ., Burnctt. .I.A. , Caron. M. & Kidd .
13 .E. 1996. The Late Albian to Ear ly Cc nomanian succession at Mont Ri so u. nea r Ro sans (Dr6me, SE France): an
integrated study (ammonites, inoceramids. planktoni c roramini rcra. nannorossi Is. oxygen and carbon iso tope s) .
Cretaceous Research. 17: 515-606.
Gartner. S. & Bukry. D. 1975. Morphology and phylogeny or
the coecoli thophycean ramily Ceratolithaceac. Journal of
Research oft he US Geological Survey, 3.: 451-465.
Jeremiah . .1 . 1996. J\ proposed Albian lO Lower Ce nomaniannannofoss il biozonation tor England and the North Sea
Basi n. Journal o(Micropalaeontology. 15(2): 97-129.
Kamptn er. I. 1950. Ubcr den s ubmikroskopischen Aulbau der
Cocco lith e n. An::. 6sterr. Akad. Wiss., Math .-Naturw. Kl. ,87 : 152-158.
Mart ini . E. 1965. Mid-Tertiary calcareous nannoplankton
ti·om Pac ifi c deep- sea cores. In : W.F . Whittard & R.B.
Brad s haw ( [ds). Submarine Geology and Geophysics.

Proceedings o(the 17th Svmposium '!f"the Colst011 ResearchSociety, London: 393 -41 I . 11utterworth s.
Martini. E. 1967. C'eratolilhina hamata n. g .. n. sp .. aus dem
Alb von N-Deutschland (Na nnopl a nkton. inccrtae sedis) .

Neues Jahrbu chfi"ir (Jeologie und Paliiontologie, ;lbhandlungen, 128(3) : 294-298 .
Pcrch-Niel se n, K. 19 79. Calca reo us nannofo ss il s from theCretaceo us between the North Sea and the Mediterranean.
llJ(;S Series A, 6 : 223-272 .
Perch-N ielse n, K. 1985a. Ce nozo ic calcareous nannofossils. In:
ll.M . Rolli . .1.£3. Sa unders & K . Pe rch- N iel se n (Ed s ).
Plankton S!raligraphy. Cambridge Uni versity Press: 427554.
Pcrch- Niclsen. K. 1985b. Mesozoic calcareous nannoto ssi ls.
In : ll.M . Bolli. .1.!3. Saunders & K. Pcrch-N iel se n (Eds).
Plankton Stratigraphy. Cambrid ge Uni ve rsity Press : 329426.
Pcrc h- Nic lsen, K. 1988 . New Lowe r Cretaceous calcareous
nannotossil species from Eng land. INA Newsletter, 10( I ):30-37 .
Raffi , I. & Flares, .I.A. 1995 . Plei stocene throu g h Miocene
ca lcareo us nannoloss il s ti·om the eastern equatorial Pac ilic
Ocean (Leg 138). Proceedings ()(the ODP, Scienlific Resulls.
138 : 233-286.
Thicrstcin . ll.R . 1974. Ca lcareous nannoplankton - Leg 26.
Deep Sea Drilling Project. IIWSD P. 26 : 619-667 .
Yarol . 0 . & Girg is. M. 1994. New taxa a nd taxonomy of so me.lurass ic to C retaceou s ca lcareou s nannofo ss il s. Ne ues.lahrbuch fi"ir Geologie und Paliion/ologie. 11 bhandlungen.
192(2): 22 1-253 .

Acknowledgements
This paper resulted from a larger study funded by an NERC/ODP Special Topic Research Fellowship (awarded 19911993). I would like to thank Prof. David Price and Dr. Paul
Sown of the Department of Geological Sciences at UCL for
helping me to continue with my research career despite
periods when funding was lacking; Drs Katharina von Sal is
and Jeremy Young for providing a usefully critical reviewof the manuscript; Shirley van Heck for her help with theLatin ; Toby Stiles for his techJ1ical photographic help; andthe ODP for providing the samp les. I would also like toextend my thanks to the Department of Geo logy at Northern Arizona University, Flagstaff for providing me with thetranquil surrou ndings which inspired me to fini sh this paper.
References
ATLAS™ Version 3 .3. Pha nerozoic Global Reconstru ction
System .
Bramlette, M .N. & Martini , E. 1964. The grea t cha nge inca l ~arcous nannoplankton ro ss ils between the Maestrichtian and Dani an. Micropalaeontology. 10 : 291-322.
Burnett ..I. A. 1996. Nannofi:Jss il s and Upper Cretaceo us (sub-)stage boundaries - state or the art. J ournal of Nannoplankton Research, 18( I ): 23-32.
Burnett, .I.A .. Youn g . .I .R. & Bown. P.R. In press. Calcareou s
nannopl ankt011 and globa l climate change. In : S ..l. C ul ver, &P.F. Rawson (Eds). Biotic Response to Global Change: Th e
Last 145 !vli/lion Years. C hapman & Hall Limited.

TAXONOMIC REFERENCE LIST

Amaurolithus Gartner & Bukry, 1975
Calculit es anfractus (Jakubowski, 1986 ) Varol &Jakubowski , 1989
Ceratolithina Martini, 1967
C. bicornuta Perch-N ielsen, 1988
C. copis
C. crux ii Perch-N ielsen, 1988 subsp. c,rux ii

63

Journal of Nannoplankton Research. 19. I. 1997 .

J A. Burne/1 : "Middle" Cretaceou s morphological diversity ...... p. 57 - 65 .

C. cruxii Perch-Nielsen, 1988 subsp. capitanea
C. duplex sp. nov. subsp. duplex
C duplex sp. nov. subsp. gemina
C. hamata Martini , 1967 subsp. hamata
C. hamata Martini , 1967 subsp.falcata

Ceratolithus Kamptner. 1950
Nannoconus Kamptner, 1931
Repagulum parvidenlatum (Detlandre & Fert in
Detlandre, 1954) Forchheimer, 1972

Seribisculllm primilivum (Thierstein, 1974) Filewicz et
al. in Wise & Wind , 1977
Triquelrorhabdulus Martini, 1965

C. naturalisteplateauensis
Ceratolithoides Bramlette & Martini, 1964

PLATElLight photomicrographs appear at 940x actual size, all with crossed-polars.
SEM photomicrographs appear at 7500x actual size.
Negatives, slides and material are stored in the Micropalaeontology Unit, UCL.
Figs 1-3: Ceratolithiua hicomuta
Sample DSDP 259-15-1, 124cm; CC8b, Middle-Upper Albian . I : Neg.# UCL-560 1-34; 2: Neg.# UCL-560 1-32 ; 3 : Neg.#
UCL-5601-31.
Fig.4: Ceratolithiua cruxii subsp. capitauea
Holotype. Sample 258-16-1, 144cm; CC9b, Upper Albian-Lower Cenomanian. Ne g.# UCL-560 1-16.
Figs 5, 6: Ceratolithiua hamata subsp.lumwta
Sample 258-17-4, 45-46cm: CC9b, Upper Albian-Lower Cenomanian. 5: Ne g.# UCL-560 1-29; 6: Ne g.# UCL-560 1-28.
Fig. 7: Ceratolithiua hamata su bsp. fa/cata
Holotype. Sample 258-14-1 , 141-142cm: CC I Oa, Lower-Upper Cenomanian. Neg.# UCL-560 1-30.
Figs 8-11, 18: Ceratolithiua cruxii su bsp. cruxii type A
8: Sample 258-17-2, 38-39cm; CC9b, Upper Albian-Lower Cenomanian; Neg.# UCL-560 1-8: 9: Sample 258-17-4, 45-46cm;
CC9b; Neg.# UCL-560 1-6 ; I 0: Sample 258-16-3 , 3 l-32cm ; CC9b; Neg.# UCL-560 1-14; 11 : Sample 258-16-5 , 36-37cm:
CC9b; Neg.# UCL-560 1-3; 18: Sample258-15-3, 35-36cm; CC9c, Lower Cenomanian; Neg.# UCL-560 1-4.
Figs 12-14, 19-23: Ceratolithiua mttura/isteplateaueusis
12: Sample 258-15-1, 141-142cm; CC I Oa, Lower-Upper Cenomanian: Neg.# UCL-560 1-27: 13: Holotype. Sample 258-153, 35-36cm; CC9c, Lower Cenomanian: Neg.# UCL-560 1-20 ; 14: Paratype. Sample as for 13 ; Ne g.# UCL-560 1-18 ; 19:
Paratype. Sample as for 13 ; Neg.# UCL-5601-35; 20 : Paratype. Sample as for 13 ; Neg.# UCL-5601-19; 21 : Paratype.
Sample as for 13; Ne g. # UCL-1 OOASA-22 ; 22 : Sample as for 12 ; Neg. # UCL-5004-6; 23 : Sample as for 12 ; Neg.# UCL5004-5.
Figs 15-17: Ceratolithiua cruxii subsp. cruxii type B
15: Sample 258-17-1, 27-28cm; CC9b, Upper Albian-Lower Cenomanian; Ne g.# UCL-560 1-9; 16: Sample 258-15-3, 3536cm; CC9c, LowerCenomanian; Neg.# UCL-560 1-21 ; 17: Sample 258-17-3, 63-64cm ; CC9b; Neg.# UCL-560 1-7.
Figs 24, 25, 29, 30: Ceratolithiua copis type C
24: Sample 258-16-5, 36-37cm; CC9b, Upper Albian-Lower Cenomanian; Neg.# UCL-560 1-12; 25: Sample 258-17-1 , 2728cm; C(::9b; Ne g.# UCL-5251-28; 29: Sample as for25; Neg.# UCL-5251-22; 30: Sample 258-17-4, 45-46cm; CC9b; Ne g.#
UCL-5601-5.
Fig.26: Cerato/ithina copis type A
Holotype . Sample 258-16-6, 15-16cm; CC9a-b, Albian/Cenomanian boundary interval ; Neg.# UCL-S250-35.
Fig.27: Ceratolithilta duplex subsp. duplex
Holotype. Sample 258-16-5, 36-37cm; CC9b, Upper Albian-Lower Cenomanian; Neg.# UCL-560 1-10.
Fig.28: Ceratolithiua duplex subsp. gemiua
Holotype. Sample 258-15-1, 141-142cm; CC IOa, Lower-Upper Cenomanian; Neg.# UCL-5250-27.
Fig.31: Ceratolithitw copis ?type B
Sample 258-15-5, 43-44cm; CC9c, Lower Cenomanian; Neg.# UCL-5250-15 .

64

J. A. Burnett: "Middle" Cretaceous morphological diversity .... .., p. 57 - 65.

Journal of Nannoplankton Research, 19, I, 1997.

PLATE 1

C. hamatasubsp.
falcataC. cruxii subsp. cruxii
type B

C. duplex
subsp. duplex

C. duplex
subsp. gemina(. copis type C

65

C. copis?type B